The subject matter described herein relates generally to methods and systems for condition monitoring of wind turbines, and more particularly, to methods and systems for monitoring the behavior of wind turbines or parts thereof during operation.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extends from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
Wind turbines are typically rated to operate 20 years or even longer. Often they are working in a hostile environment, for example in a off-shore wind park, with high temperature cycles, and at high and strongly fluctuating wind speeds. This typically results in high loads which may reduce the life time of the wind turbine and their components, respectively. For example, a gearbox arranged inside the nacelle as part of the wind turbines drivetrain as well as the bearings of the drivetrain may have live times of only a few years due to heavy loads caused by rapid changes of wind speed and/or wind direction.
Furthermore, expected live times of wind turbine components may deviate from the actual life times under fluctuating external conditions which are typically only approximately known during design of the wind turbine and the wind park, respectively. According to the industrial standard IEC 61400-1, the wind turbines are designed and checked to bear the external conditions on site. However, these conditions are either based on short-term measurements on site or on long-term measurements of weather station nearby and may thus be not sufficiently reliable. For safety reasons, wind turbines are, therefore, typically inspected and maintained, respectively, in comparatively short regular intervals. This typically increases maintenance costs and down times of the wind turbine. Furthermore, possible margins of the live time of wind turbine components may not fully be used.
Transducers based condition monitoring systems for detecting drivetrain issues during wind turbine operation may be used. However, these systems may be very complex and/or may only detect progressed wear or attrition of drivetrain components.
In view of the above, there is a desire for wind turbine and a method for monitoring conditions of the wind turbine which allow for a sensitive and reliable assessment of loads and remaining life time of the wind turbine and/or the wind turbine components.